This invention relates to tire mold opening and especially to opening large molds for earthmover tires using a hoist. Each of these large tires is placed in a mold having an upper mold half and a lower mold half and then cured in a heater. After curing of the tire, the mold has been transported to a mold separation floor where the lower mold half has been held against the floor by magnets. The upper mold half has then been lifted away from the lower mold half by a hoist. Difficulties have been encountered with this procedure because frequently the lower mold half is lifted off the floor during the mold separation and then falls back on the floor causing damage to the floor and to the magnets. Also, the capacity of the hoist has been substantially more than that necessary to transfer the mold because not only must the hoist lift the mold, but it must also provide the necessary force to separate the lower mold half from the upper mold half and pull the cured tire out of the mold halves.
In U.S. Pat. No. 2,832,990, it is proposed to use parallel bars and a lever to separate mold halves. In U.S. Pat. No. 3,154,814, it is proposed to separate an upper mold half from a lower mold half by hydraulic jacks after which the upper mold half is lifted off the lower mold half by a hoist.
The present invention is directed to utilizing the hoist and the weight of the entire mold to actuate levers pivotally mounted on the upper mold half to separate the upper mold half from the lower mold half utilizing the total weight of the mold and the leverage provided to generate the force necessary to separate the mold halves and pull the tire out of the mold halves.
In accordance with one aspect of the invention, there is provided a tire mold opener for separating an upper mold half from a lower mold half characterized by a lever pivotally mounted on the upper mold half having a separating end engageable with the lower mold half, a lifting end engageable with a hoist for rotating the lever in a direction to press the separating end against the lower mold half while lifting the upper mold half away from the lower mold half to open the tire mold.